Computer networks are being used increasingly frequently, in particular also in the automotive industry. So-called Controller Area Network interfaces (CAN-IC) which are constructed as integrated circuits are known. The connection of the individual network subscribers occurs via a databus which has, for example, two signalling lines. The information of the subscribers is transmitted via these lines. Any failure of one of the two signalling lines due to short circuit to earth or to the voltage supply or a break of the lines results in the entire network collapsing. This is then also the case if a short circuit occurs between the two bus lines or if one of the subscribers is defective.
The individual subscribers of a network have, in addition to the CAN-IC, a so-called bus interface. This is a special wiring of the CAN-ICs, by means of which it is intended to detect errors occurring on the bus lines.
However, systems of this kind do not permit a central monitoring of the functioning of the databus or of the functioning of individual subscribers of a computer network.